Add Spline from file method and example

[fluidnumerics-joe]

This PR brings in a feature to read in a Spline curve from a file. A 2-D example is provided for the EastCoastUS domain under Examples/2D/EastCoastUS

This PR was created to replace https://github.com/trixi-framework/HOHQMesh/pull/26. Relative to https://github.com/trixi-framework/HOHQMesh/pull/26, this PR does not have the bottom-topography-from-file branch merged in.

[codecov[bot]]

Codecov Report

Merging #32 (7263f1f) into main (370e50f) will increase coverage by 0.08%. The diff coverage is 85.00%.

@@            Coverage Diff             @@
##             main      #32      +/-   ##
==========================================
+ Coverage   57.41%   57.49%   +0.08%     
==========================================
  Files          65       65              
  Lines        9557     9580      +23     
==========================================
+ Hits         5487     5508      +21     
- Misses       4070     4072       +2     

Flag	Coverage Δ
unittests	57.49% <85.00%> (+0.08%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ce/Curves/DiscreteCurves/FRSegmentedCurveClass.f90	71.91% <0.00%> (ø)
Source/Testing/MeshingTests.f90	93.58% <ø> (ø)
Source/Project/Model/SMModel.f90	59.15% <82.14%> (+0.70%)	:arrow_up:
...rce/Curves/ContinuousCurves/SMSplineCurveClass.f90	95.31% <100.00%> (+0.44%)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 370e50f...7263f1f. Read the comment docs.

[fluidnumerics-joe]

@DavidAKopriva, Merging now :+1: